aes-ctr.c
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00001 /*
00002  * AES-128 CTR
00003  *
00004  * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
00005  *
00006  * This program is free software; you can redistribute it and/or modify
00007  * it under the terms of the GNU General Public License version 2 as
00008  * published by the Free Software Foundation.
00009  *
00010  * Alternatively, this software may be distributed under the terms of BSD
00011  * license.
00012  *
00013  * See README and COPYING for more details.
00014  */
00015 
00016 #include "includes.h"
00017 
00018 #include "common.h"
00019 #include "aes.h"
00020 #include "aes_wrap.h"
00021 
00030 int aes_128_ctr_encrypt(const u8 *key, const u8 *nonce,
00031                         u8 *data, size_t data_len)
00032 {
00033         void *ctx;
00034         size_t j, len, left = data_len;
00035         int i;
00036         u8 *pos = data;
00037         u8 counter[AES_BLOCK_SIZE], buf[AES_BLOCK_SIZE];
00038 
00039         ctx = aes_encrypt_init(key, 16);
00040         if (ctx == NULL)
00041                 return -1;
00042         os_memcpy(counter, nonce, AES_BLOCK_SIZE);
00043 
00044         while (left > 0) {
00045                 aes_encrypt(ctx, counter, buf);
00046 
00047                 len = (left < AES_BLOCK_SIZE) ? left : AES_BLOCK_SIZE;
00048                 for (j = 0; j < len; j++)
00049                         pos[j] ^= buf[j];
00050                 pos += len;
00051                 left -= len;
00052 
00053                 for (i = AES_BLOCK_SIZE - 1; i >= 0; i--) {
00054                         counter[i]++;
00055                         if (counter[i])
00056                                 break;
00057                 }
00058         }
00059         aes_encrypt_deinit(ctx);
00060         return 0;
00061 }


wpa_supplicant
Author(s): Package maintained by Blaise Gassend
autogenerated on Thu Jan 2 2014 11:26:36